US4518913A - Measuring probes - Google Patents

Measuring probes Download PDF

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Publication number
US4518913A
US4518913A US06/379,344 US37934482A US4518913A US 4518913 A US4518913 A US 4518913A US 37934482 A US37934482 A US 37934482A US 4518913 A US4518913 A US 4518913A
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US
United States
Prior art keywords
jaws
actuator
ring
open position
probe
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US06/379,344
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English (en)
Inventor
Rodney P. Jackson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
HEME INTERNATIONAL LIMITD A CORP OF GREAT BRITAIN
H E M E INTERNATIONAL Ltd
Original Assignee
H E M E INTERNATIONAL Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by H E M E INTERNATIONAL Ltd filed Critical H E M E INTERNATIONAL Ltd
Assigned to H.E.M.E. INTERNATIONAL LIMITD, A CORP. OF GREAT BRITAIN reassignment H.E.M.E. INTERNATIONAL LIMITD, A CORP. OF GREAT BRITAIN ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: JACKSON, RODNEY P.
Application granted granted Critical
Publication of US4518913A publication Critical patent/US4518913A/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
    • G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
    • G01R15/20—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices
    • G01R15/202—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices using Hall-effect devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
    • G01R1/20—Modifications of basic electric elements for use in electric measuring instruments; Structural combinations of such elements with such instruments
    • G01R1/22—Tong testers acting as secondary windings of current transformers
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/145—Indicating the presence of current or voltage
    • G01R19/15—Indicating the presence of current

Definitions

  • the invention relates to a measuring probe, in particular, a measuring probe which, in use, forms a magnetic circuit around a conductor in order to obtain a signal related to the magnitude of the electric current flowing in the conductor, and to a measuring instrument having such a probe.
  • Instruments having probes of this kind which enable an electric current to be measured without interrupting or otherwise affecting the current flowing have been described previously and, for reasons which will become apparent, referred to as "clip-on" meters.
  • the present invention arises from the realisation, by the inventor, that, once the ring of magnetic material has been interrupted by an initial relative displacement of the jaws, the magnetic field in the magnetic circuit is substantially reduced and the force required to complete the opening of the jaws is similarly reduced.
  • a measuring probe of the kind in which a complete or substantially complete ring of magnetisable material is formed around a conductor comprising a set of opposed jaws comprising magnetisable material and relatively movable between an open position in which the ring is broken and the jaws can be placed over a conductor and a closed position in which the jaws meet around the conductor and the ring of magnetisable material is at least substantially complete characterised in that the jaws are movable from the closed position to the open position by the action of an opening mechanism with an actuator so constructed and arranged that initial pressure on the actuator urges the jaws apart from the closed position at a first mechanical advantage and, after an initial movement of the actuator, subsequent pressure urges the jaws toward the fully open position at a second lower mechanical advantage.
  • the value of the first mechanical advantage is preferably selected to permit comfortable opening of the jaws by manual operation of the actuator when a current at the upper end of the range to be measured is flowing through a conductor between the jaws.
  • the value of the second mechanical advantage may be selected to permit the desired opening of jaws, again with a pressure that can be applied to the actuator manually without undue effort, whilst allowing a desired compact construction.
  • the ratio of said first mechanical advantage to said second mechanical advantage to be at least 3:1.
  • the magnetic field in the ring of magnetisable material is related to the current flowing in the conductor between the jaws, and the probe may therefore additionally comprise means for generating a signal related to the magnetic field in the ring (and hence the current flowing in the conductor).
  • the said means for generating a signal may be, for example, a Hall generator (i.e. a chip of material which exhibits the Hall effect, for example, silicon or gallium arsenide) located in a gap in the ring of magnetisable material with electrical connectors for applying a potential difference across the Hall generator in a direction substantially perpendicular to the magnetic field.
  • the Hall generator will generate a potential difference, related to the magnetic field, in a direction perpendicular to both the magnetic field and the applied potential difference and, by measuring the generated potential difference, a measure of the magnetic field, and hence the current flowing in the conductor between the jaws, may be obtained.
  • the measuring probe comprises a Hall generator mounted in a gap in the ring of magnetisable material, first electrical connections for applying a potential difference across the Hall generator in a direction substantially perpendicular to the magnetic field from the ring and second electrical connections to the Hall generator along a line substantially perpendicular to the direction of said magnetic field and the direction of a potential difference applied between said first connections.
  • the means for generating a signal may be arranged for connection to means for measuring the signal generated and means for displaying the resulting measurement.
  • a measuring instrument comprising a probe in accordance with the invention, means for generating a signal related to the magnetic field in the ring of magnetisable material in the probe, means for measuring the signal generated and means for displaying the resulting measurement.
  • FIG. 1 is a plan view of a Hall effect clip-on ammeter with a probe in accordance with the invention and a digital display;
  • FIG. 2 is a plan view of the inside of the ammeter shown in FIG. 1 with the front cover removed;
  • FIG. 3 is a schematic representation of the Hall generators and their connection to the display in the ammeter of FIGS. 1 and 2.
  • FIG. 4 is a plan view, partially cut away, of a modified form of the handle shown in FIG. 2.
  • a Hall effect clip-on ammeter generally designated 1, comprises a body portion 2 on which is mounted a digital display 3 for display of measurements made.
  • a pair of jaws 4 and 5 are also mounted on body portion 2, the jaw 5 being movable between the closed position in which it is shown and an open position 6 indicated in dots.
  • An actuator in the form of handle 7, for operating the mechanism which opens the jaws, and an on-off switch 8 are also mounted on body portion 2.
  • a ring of magnetic material mounted in jaws 4 and 5 is indicated by dotted lines.
  • gaps 11, 12 in the ring in which Hall generators are mounted are provided and, if desired, other small gaps may be provided.
  • air gaps in the magnetic circuit make it susceptible to the influence of stray fields and, to avoid inaccuracies due to stray fields, the ring of magnetisable material is substantially complete.
  • the jaw 4 is mounted in fixed position relative to the body portion 2 by rivets 14, 15.
  • the jaw 5 is pivotally mounted relative to the body portion 2 and jaw 4 on pivot 16, and has a short limb 17, ending in a fork formed by prongs 18 and 19, extending beyond the pivot 16 in the direction of handle 7.
  • the short limb 21 bears on the lower edge of the jaw 5 at the point marked 23 whilst the longer limb 22 contacts the handle 7 at 24.
  • the handle 7 is mounted on a pivot 25 at the base of the body portion 2 and the end 26 of the handle remote from the pivot 25 is located between prongs 18 and 19 forming the bifurcated end of the short limb 17 of the movable jaw 5.
  • the jaw 5 is urged towards the fixed jaw 4 by a spring 29 mounted between the jaws and attached to them at 27 and 28 respectively.
  • the jaws are opened against the pressure of spring 29 by operation of the handle 7, placed around a conductor in which the current is to be measured and then allowed to close under the action of spring 29.
  • the ring of magnetic material concentrates the magnetic field resulting from the passage of the current through the conductor so that the Hall generators mounted at 11 and 12 are subjected to a magnetic field related to the magnitude of the current flowing in the conductor.
  • the Hall generators 32, 33 and connections thereto are shown schematically in FIG. 3. A potential difference is applied across each of the Hall generators 32, 33, in a plane perpendicular to the direction of the magnetic field via electrical connections 34, 35 and 36, 37.
  • the Hall generators each produce a potential difference at right angles to both the magnetic field and the applied potential difference.
  • the potential differences generated by the Hall generators which depend on the magnetic field and hence the current flowing in the conductor between the jaws, are applied via connections 38, 39 and 40, 41 to measuring circuitry 42.
  • the measuring circuitry 42 processes the signals to produce a reading, on the digital display, of the magnitude of the current being measured.
  • the jaws To remove the ammeter from the conductor, the jaws must be opened. If a substantial current is flowing (e.g. 100 amps or more), there is a substantial magnetic field in the magnetic ring acting to retain the jaws in the closed position and, if the ammeter is to be removed without switching off the current, this force must be overcome.
  • a substantial current e.g. 100 amps or more
  • FIG. 2 is regarded as approximately to scale, it will be appreciated that point 24 lies approximately midway between pivots 16 and 25; thus an initial clockwise rotation of the handle 7 through a small angle X° will cause the crank 20 and hence the jaw 5 to rotate approximately X° anti-clockwise from the jaws closed position.
  • the end 26 of the handle comes into contact with prong 19 and the continued rotation of the jaw 5 depends on the displacement of prong 19 by the handle.
  • the point of contact between prong 19 and handle 7 is approximately 7/8 of the distance between pivots 25 and 16 so that a further rotation of the handle clockwise through an angle X° will result in a corresponding anti-clockwise rotation of the jaw 5 through an angle of approximately 7X°.
  • the ratio of the first mechanical advantage to the second mechanical advantage is approximately 7:1.
  • an additional spring member may be incorporated between the end 26 of the handle 7 and prong 19 of the short limb 17 of the movable jaw 5. Such a spring member may be mounted on the handle as illustrated in FIG. 4.
  • the modified form of handle 7' illustrated in FIG. 4 incorporates a spring member 43 in the form of a shaped strip of spring steel riveted to the handle 7' at about its mid-point.
  • the end 44 of spring bears against prong 19 and the spring member 43 exerts a pressure on the handle 7' to maintain it in a rest position with the jaws closed.
  • the spring member 43 is deflected and the jaws open as a result of rotation of crank 20, which bears on jaw 5, about pivot 16.
  • Spring member 43 becomes fully deflected before the end 26' of the handle 7' catches up with prong 19 and comes into contact with it.
  • prong 19 moves with the end 26' and the jaw 5 pivots at an increased angular rate so that contact at 23 between jaw 5 and the short limb 21 of the crank 20 is broken.
  • the probe is constructed as an integral part of the ammeter, it will be appreciated that this is not essential and the probe may be constructed separately from the remaining parts of the meter and connected to them electrically.
  • the probe is not necessarily associated with a meter. It may, for example, be used as part of a control system. In this case, the signal from the probe may be used as an input to the control system so that the system can respond in a desired manner to the magnitude of the current flowing in a conductor between the jaws of the probe.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
  • Magnetic Heads (AREA)
  • Mechanical Treatment Of Semiconductor (AREA)
  • Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
  • Ultra Sonic Daignosis Equipment (AREA)
  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
  • Measuring Magnetic Variables (AREA)
US06/379,344 1981-05-22 1982-05-18 Measuring probes Expired - Fee Related US4518913A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8115877 1981-05-22
GB8115877A GB2099159B (en) 1981-05-22 1981-05-22 Measuring probe

Publications (1)

Publication Number Publication Date
US4518913A true US4518913A (en) 1985-05-21

Family

ID=10522022

Family Applications (1)

Application Number Title Priority Date Filing Date
US06/379,344 Expired - Fee Related US4518913A (en) 1981-05-22 1982-05-18 Measuring probes

Country Status (5)

Country Link
US (1) US4518913A (de)
EP (1) EP0067527B1 (de)
AT (1) ATE16531T1 (de)
DE (1) DE3267378D1 (de)
GB (1) GB2099159B (de)

Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USD288301S (en) 1983-12-21 1987-02-17 Construction D'Appereillage Clamp-on current probe
US4656418A (en) * 1986-01-27 1987-04-07 Snap-On Tools Corporation Molded clamp-type ammeter probe
USD292177S (en) 1985-03-08 1987-10-06 Lin Dong-Chang Clamp-on multimeter or similar article
US4717872A (en) * 1985-01-28 1988-01-05 Watt Watcher Inc. Device for monitoring consumption of electrical power
US4913153A (en) * 1987-11-13 1990-04-03 Florida International University Personal dosimeter
USD315522S (en) 1988-04-21 1991-03-19 Societe Chauvin Arnoux Current probe
US5029304A (en) * 1988-12-28 1991-07-02 Pitney Bowes Inc. Sensor with absolute digital output utilizing Hall Effect devices
US5039970A (en) * 1989-05-17 1991-08-13 Minnesota Mining And Manufacturing Company Self-aligning core for induction coil
USD359006S (en) 1994-04-05 1995-06-06 Fluke Corporation Digital clamp meter
USD401874S (en) 1996-10-16 1998-12-01 Societe Chauvin Arnoux Clamp-on current probe
FR2778032A1 (fr) * 1998-04-24 1999-10-29 Mos Ind Dispositif pique-cable
EP1213189A1 (de) * 2000-12-06 2002-06-12 Hella KG Hueck & Co. Einrichtung zur Überwachung eines Bordnetzes eines Fahrzeuges
US20030011362A1 (en) * 2001-07-12 2003-01-16 Thomas Gohlsch Current transformer
US20050127895A1 (en) * 2003-12-10 2005-06-16 Functional Devices, Inc. Current sensor wire clamp
US7043380B2 (en) 2003-09-16 2006-05-09 Rodenberg Iii Ernest Adolph Programmable electricity consumption monitoring system and method
US20120051034A1 (en) * 2010-09-01 2012-03-01 Shaw-Lin Liu Hook meter with improved illumination
DE102011102978A1 (de) * 2011-05-23 2012-11-29 Phoenix Contact Gmbh & Co. Kg Strommessumformer
US20150204995A1 (en) * 2013-07-29 2015-07-23 SeeScan, Inc. Inductive clamp devices, systems, and methods
US9366698B2 (en) 2013-01-18 2016-06-14 Chauvin Arnoux Clamp including fixed and movable jaws for measuring a ground loop current
US20160231362A1 (en) * 2013-09-30 2016-08-11 Lem Intellectual Property Sa Clip-on current transducer or current transformer
CN106771378A (zh) * 2016-12-07 2017-05-31 国家电网公司 一种无线测试钳手持操作杆
DE102016123255A1 (de) 2016-12-01 2018-06-07 Phoenix Contact Gmbh & Co. Kg Vorrichtung zur Messung von in einem elektrischen Leiter fließendem Strom
JP2020003292A (ja) * 2018-06-27 2020-01-09 日置電機株式会社 クランプセンサおよび測定装置
US11215643B2 (en) * 2018-02-19 2022-01-04 Hioki E.E. Corporation Clamp sensor and measuring device

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3611864A1 (de) * 1986-04-09 1987-10-15 Mueller & Weigert Zangenanlege-messgeraet
EP0263154B1 (de) * 1986-04-09 1992-01-02 Müller und Weigert GmbH Multifunktionsmessgerät
US4998060A (en) * 1989-07-12 1991-03-05 Pacific Scientific Company Fault indicator with hot stick clamping mechanism
GB2235053B (en) * 1989-07-25 1993-08-11 Electricity Council Method of and apparatus for identifying an electrical cable
GB2259574B (en) * 1991-09-12 1995-08-30 Heme Int Ltd Measuring devices
GB9818791D0 (en) * 1998-08-28 1998-10-21 Sun Electric Uk Ltd Method and apparatus for automotive and other testing
GB2353601B (en) * 1998-08-28 2002-01-23 Snap On Equipment Ltd Method and apparatus for automotive and other testing
DE10036664A1 (de) * 2000-07-26 2002-02-14 Metrawatt Gmbh Gossen Digitales Multimeter

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1924039A (en) * 1932-12-07 1933-08-22 Crompton Parkinson Ltd Electrical measuring instrument
US2663845A (en) * 1950-01-28 1953-12-22 Samuel J Koch Clamp on type electrical measuring instrument
US2901705A (en) * 1955-06-06 1959-08-25 Daystrom Inc Instrument case
US3168698A (en) * 1960-06-27 1965-02-02 Fed Pacific Electric Co Electrical clamp-on meter with swivel connected tongs

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3199026A (en) * 1961-05-01 1965-08-03 Gen Precision Inc D.-c. clamp-on meter including a hall plate flux detector
FR2334112A1 (fr) * 1975-12-04 1977-07-01 Marechaux Dubost & Cie Pince amperemetrique
US4059798A (en) * 1976-03-08 1977-11-22 F. W. Bell, Inc. Method and apparatus for measuring the current flowing in a workpiece

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1924039A (en) * 1932-12-07 1933-08-22 Crompton Parkinson Ltd Electrical measuring instrument
US2663845A (en) * 1950-01-28 1953-12-22 Samuel J Koch Clamp on type electrical measuring instrument
US2901705A (en) * 1955-06-06 1959-08-25 Daystrom Inc Instrument case
US3168698A (en) * 1960-06-27 1965-02-02 Fed Pacific Electric Co Electrical clamp-on meter with swivel connected tongs

Cited By (28)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USD288301S (en) 1983-12-21 1987-02-17 Construction D'Appereillage Clamp-on current probe
US4717872A (en) * 1985-01-28 1988-01-05 Watt Watcher Inc. Device for monitoring consumption of electrical power
USD292177S (en) 1985-03-08 1987-10-06 Lin Dong-Chang Clamp-on multimeter or similar article
US4656418A (en) * 1986-01-27 1987-04-07 Snap-On Tools Corporation Molded clamp-type ammeter probe
US4913153A (en) * 1987-11-13 1990-04-03 Florida International University Personal dosimeter
USD315522S (en) 1988-04-21 1991-03-19 Societe Chauvin Arnoux Current probe
US5029304A (en) * 1988-12-28 1991-07-02 Pitney Bowes Inc. Sensor with absolute digital output utilizing Hall Effect devices
US5039970A (en) * 1989-05-17 1991-08-13 Minnesota Mining And Manufacturing Company Self-aligning core for induction coil
USD359006S (en) 1994-04-05 1995-06-06 Fluke Corporation Digital clamp meter
USD401874S (en) 1996-10-16 1998-12-01 Societe Chauvin Arnoux Clamp-on current probe
FR2778032A1 (fr) * 1998-04-24 1999-10-29 Mos Ind Dispositif pique-cable
EP1213189A1 (de) * 2000-12-06 2002-06-12 Hella KG Hueck & Co. Einrichtung zur Überwachung eines Bordnetzes eines Fahrzeuges
US20030011362A1 (en) * 2001-07-12 2003-01-16 Thomas Gohlsch Current transformer
US7043380B2 (en) 2003-09-16 2006-05-09 Rodenberg Iii Ernest Adolph Programmable electricity consumption monitoring system and method
US20050127895A1 (en) * 2003-12-10 2005-06-16 Functional Devices, Inc. Current sensor wire clamp
US20120051034A1 (en) * 2010-09-01 2012-03-01 Shaw-Lin Liu Hook meter with improved illumination
DE102011102978B4 (de) 2011-05-23 2018-05-17 Phoenix Contact Gmbh & Co. Kg Strommessumformer
DE102011102978A1 (de) * 2011-05-23 2012-11-29 Phoenix Contact Gmbh & Co. Kg Strommessumformer
US9165709B2 (en) 2011-05-23 2015-10-20 Phoenix Contact Gmbh & Co Kg Current transformer
US9366698B2 (en) 2013-01-18 2016-06-14 Chauvin Arnoux Clamp including fixed and movable jaws for measuring a ground loop current
US20150204995A1 (en) * 2013-07-29 2015-07-23 SeeScan, Inc. Inductive clamp devices, systems, and methods
US9632199B2 (en) * 2013-07-29 2017-04-25 SeeScan, Inc. Inductive clamp devices, systems, and methods
US20160231362A1 (en) * 2013-09-30 2016-08-11 Lem Intellectual Property Sa Clip-on current transducer or current transformer
US10295574B2 (en) * 2013-09-30 2019-05-21 Lem Intellectual Property Sa Clip-on current transducer or current transformer
DE102016123255A1 (de) 2016-12-01 2018-06-07 Phoenix Contact Gmbh & Co. Kg Vorrichtung zur Messung von in einem elektrischen Leiter fließendem Strom
CN106771378A (zh) * 2016-12-07 2017-05-31 国家电网公司 一种无线测试钳手持操作杆
US11215643B2 (en) * 2018-02-19 2022-01-04 Hioki E.E. Corporation Clamp sensor and measuring device
JP2020003292A (ja) * 2018-06-27 2020-01-09 日置電機株式会社 クランプセンサおよび測定装置

Also Published As

Publication number Publication date
GB2099159A (en) 1982-12-01
EP0067527B1 (de) 1985-11-13
DE3267378D1 (en) 1985-12-19
EP0067527A1 (de) 1982-12-22
ATE16531T1 (de) 1985-11-15
GB2099159B (en) 1985-04-11

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AS Assignment

Owner name: H.E.M.E. INTERNATIONAL LIMITD PRESCOT ROAD, ST. HE

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:JACKSON, RODNEY P.;REEL/FRAME:004003/0155

Effective date: 19820507

Owner name: H.E.M.E. INTERNATIONAL LIMITD, A CORP. OF GREAT BR

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:JACKSON, RODNEY P.;REEL/FRAME:004003/0155

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Year of fee payment: 4

LAPS Lapse for failure to pay maintenance fees
FP Lapsed due to failure to pay maintenance fee

Effective date: 19930523

STCH Information on status: patent discontinuation

Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362